Drawbench apparatus



Oct. 12, 1965 s. E. WELLS 3,210,983

DRAWBENCH APPARATUS Filed Oct. 31, 1963 2 Sheets-Sheet 1 U1 OI m (I) 0If) m l-L Q E w 05 t0 m N L N w E (D m Z O N (1) '1 w o h) a v H In 5 ZO N (Q INVENTOR.

m g SHELDON E. WELLS l B E l W his ATTORNEY.

Oct. 12, 1965 s. E. WELLS DRAWBENCH APPARATUS Filed Oct. 31, 1965 2Sheets-Sheet z &

SHELDON E. WELLS if/W his ATTORNEY.

q: INVENTOR. .9 LL

United States Patent 3,210,983 DRAWBENCH APPARATUS Sheldon E. Wells,Youngstown, Ohio, assignor to Mannesmann-Meer, Inc., Youngstown, Ohio, acorporation of Pennsylvania Filed Oct. 31, 1963, Ser. No. 320,454 11Claims. (Cl. 72291) This invention relates to drawbenches adapted todraw one or more tubes or the like through a corresponding number ofdies. More specifically, the invention relates to apparatus forpreventing damage to newly-drawn tubes as a result of their beingpropelled forwardly at the completion of a draw.

As is well known to those skilled in the art, a drawbench employs, as abasic component, a circular die through which a workpiece, such as atube, is drawn in order to elongate it and reduce its diameter. In thedrawing operation, the end-s of tubes to be drawn are passed through acorresponding number of dies and engaged by gripper jaws carried on adraw carriage or dolly which travels on a track extending parallel .tothe central axis of the die on one side thereof. In the drawingoperation, the draw carriage is forced along its track structure awayfrom the die, thereby pulling the tubes through the dies. in the usualcase, the draw carriage is driven by means of an electric motor or fluidmotor, connected to the cartriage through a chain or cable drivearrangement.

It is :a common occurrence in the drawing of tubes for the same to jumpforwardly with considerable force as their trailing ends leave the dies,the reason being that the tubes are under substantial tension during thedrawing operation, and the sudden release of such tension is accompaniedby a release of energy which propels the tubes forwardly withconsiderable force. The action is somewhat analogous to that occurringwhen one end of a stretched elastic band is released and snaps forwardlytoward the other end. In the drawing of long, slender tubes ofthin-walled section this condition is a particularly serious problem inthat the forward ends of the tubes are driven against the draw carriageand are often buckled and rendered unsuitable for a subsequent drawingoperation, or partially so. That is, when a long slender tube is drivenagainst the draw carriage, shock waves develop along its length. Ifthese waves are such as to produce bends in the tube of such magnitudeas to exceed its elastic limit, permanent deformation will result,thereby producing the buckled or dog-legged condition mentioned. Thiscondition may be severe enough to render the tube unsuitable for furtherprocessing .and, even if minor, makes the stocking or piling of thetubes diificult for reasons which will be apparent fro-m a considerationof the bent condition of the tubes.

In the past, various schemes have been proposed in an attempt to preventbuckling or dog-legging of the forward ends of the tubes. One suchproposal calls for shock absorbers on the draw carriage designed toabsorb the kinetic energy of the tubes as they jump forwardly at thecompletion of a draw. Another proposal utilizes inclined planes ordeflectors designed to direct the tube down beneath the draw carriagewhere it can expend its energy by moving along a raceway beneath thedraw carriage track. Neither of these systems, however, is completelysuccessful in eliminating a dog-legged condition and raise auxiliaryproblems in the design of the draw carriage, tube receiving trough orother parts of the drawbench.

As an overall object, the present invention seeks to provide new andimproved apparatus for preventing damage to the forward ends ofnewly-drawn tubes at the completion of a drawing operation, whichapparatus over- 3,210,983 Patented Oct. 12, 1965 comes theaforementioned and other disadvantages of prior art systems of thistype.

More specifically, an object of the invention is to provide means in adrawbench for laterally restraining a tube as it is being drawn, wherebythe restraining means will prevent waves from developing in the tube andhence, permanent deformation resulting in dog-legging.

Still another object of the invention is to provide means in drawbenchapparatus for evenly and uniformly stacking newly-drawn tubes in areceiving bin or the like to facilitate their further processing.

In accordance with one embodiment of the invention, a plurality of paneldevices, each of normally separated upper and lower parts, are spacedalong the drawbench track structure and designed such that their upperand lower parts come together or close in succession behind the drawcarriage as it moves down the track during a drawing operation. As eachof the panel devices closes, it envelops or surrounds, but does nottouch, the tubes being drawn so as to provide a plurality of openings insuccessive panel devices through which the tubes pass. At the completionof the drawing operation when the tubes giump forwardly .and strike thedraw carriage, the openings in the panel devices will serve to laterallyrestrict the tubes. Consequently, since the tubes cannot now bedeflected laterally in any appreciable amount by the development ofshock waves, they cannot bend to an extent exceeding their elastic limitand permanent bends or dog legs cannot develop. Finally, when the drawcarriage returns to the dies following a drawing operation, the upperand lower parts of all panel devices separate to permit the carriage tomove toward the dies preparatory to a succeeding drawing operation.

Preferably, the upper and lower parts of each panel device are mountedfor pivotal movement about a common horizontal axis in what might betermed a scissors arrangement with the parts being rotated about theircommon axis int-o abutment as they are passed by the draw carriageduring the drawing operation, and rotated in opposite directions so asto separate and permit the draw carriage to pass during its returnstroke. As will be seen, downward movement of the lower part of eachpanel device deposits the newly-drawn tubes onto an inclined run-outtable where they roll into a neat bundle preparatory to furtherprocessing. Thus, contrary to most prior art drawbenches whereindifliculty is experienced in attempting to pile the newly-drawn tubes inneat bundles, the present invention has the auxiliary advantage in thatit eliminates such problems.

The above and other objects and features of the invention will becomeapparent from the following detailed description taken in connectionwith the accompanying drawings which form a part of this specification,and in which:

FIGURE 1 is a partially broken-away top view of the dies, trackstructure, draw carriage and associated apparatus of the drawbench ofthe invention;

FIG. 2 is a side view of the apparatus shown in FIG. 1;

FIGS. 3A and 3B show the manner in which a drawn tube is bent ordog-legged due to the release of kinetic energy at the completion of adraw; and

FIG. 4 is a cross-sectional view taken substantially along line TVW ofFIG. 1, showing in detail one of the panel devices of the invention inassociation with the pneumatic and electrical control system therefor.

Referring now to the drawings, and particularly to FIGS. 1, 2 and 4, thenumeral 10 represents generally the main framework of a draw benchassembly which is comprised of a plurality of frame sections 12. One ofsaid frame sections is shown in detail in FIG. 4 and comprises acastingof generally C-shaped form having a lower portion 14, anupstanding portion 16 and an upper cantilever beam section 18. At theforward end of the beam section 18 is a downwardly-depending integralportion 20 which carries at its lower end a track support 22. Thesupport 22 is one of a complementary pair, a second support 24 beingcarried by the upstanding portion 16, as shown.

In the complete drawbench assembly as shown in FIGS. 1 and 2, there area plurality of frame sections 12 mounted in spaced relation. Carried bythe plurality of supports 22 and 24 of such frame sections are spacedtracks 26 and 28 (FIG. 4) which support and guide a draw carriage 30 forlongitudinal movement throughout the length of the drawbench, as will besubsequently developed herein.

Below each of the track supports 22 and 24, and extending throughopenings 32 in the lower portion 14 of each frame section 10 (FIG. 4)are guiding and supporting channels 34 and 36 for a pair of spaced drawchains 38 and 40 which are employed to draw the carriage 30 along itsguided path on the tracks 26 and 28 during a drawing operation. The drawchains 38 and 40 are connected to the forward end of the carriage 30 asat 39 and to its other end through an equalizer bar 41. Suitablesprockets 42 (see FIG. 2) are provided at each end of the respectivetraverses of the chains 38 and 40, and around which the chainsarticulate.

At the trailing end of the drawbench assembly as viewed in FIGS. 1 and 2is a heavy-duty drive motor 44 and gear reducer 46, the latter of whichhas driving connection with the sprockets 42 at the right-hand end ofthe assembly to thereby impart a driving force to the chains 38 and 40.Preferably, the motor 44 is of the reversible type such that it mayrotate the sprockets 42 to move the draw carriage 30 to the right duringthe drawing operation or to the left during the return stroke of thedraw carriage. At the left end of the drawbench assembly 10 shown inFIGS. 1 and 2 is a die block 48 provided with a plurality of diespositioned in side-by-side relationship and through which tubes 50 aredrawn.

In the drawing operation, the tubes to be drawn are loaded onto a rack52 extending along the drawbench frame 10 at the forward portion thereofand supported on the tops of the cantilever beam portions 18 of eachframe section 12 as shown in FIG. 4. Thereafter, the tubes are loadedonto mandrels, not shown herein, but positioned to the left of the dieblock 48 in FIGS. 1 and 2. After the tubes are loaded onto the mandrels,their swaged or reduced diameter ends are inserted through the openingsin the dies and gripped by gripper jaws on the draw carriage 30, suchgripper jaws being hereinafter described in greater detail. After theforward ends of the tubes are thus gripped by the gripper jaws, themotor 44 is actuated to force the draw carriage 30 away from the dieblock 48, thereby pulling the tubes 50 through the dies while reducingtheir diameters and increasing their lengths.

The operation of the drawbench is schematically illustrated in FIGS. 3Aand 3B. In FIG. 3A, a tube 54 being drawn through a die 56 is insubstantial tension and has its forward swaged or reduced diameter end58 engaged by grip bits 60 and 62 carried on the draw carriage,schematically illustrated at 64. The grip bits 60 and 62 are mounted inconverging guideways such that as the draw carriage 64 is pulled awayfrom the die 56, the bits 60 and 62 are forced into grippingrelationship with the reduced diameter end 58.

The completion of the drawing operation is illustrated in FIG. 3B whenthe trailing end of the tube 54 passes through the die 56. As wasexplained above, passage of the trailing end through the die 56 isaccompanied by a release of energy which propels the tube forwardly,thereby moving the grip bits 60 and 62 backwardly and releasing theforward reduced diameter end 58 of the tube. This causes the tube 54 tostrike the draw carriage 64. When this occurs,shock waves are developedin the tube 54 as illustrated in FIG. 3B; and if the magnitude of theseshock waves is great enough, and it often is, the elastic limit of thetube 54 will be exceeded whereby perma nent bends or dog-legs will beproduced in the tube, usually at the forward end thereof. In otherwords, deformation occurs at the forward end of the tube, not ordinarilyat its trailing end.

In accordance with the present invention, the development of shock wavesand the possibility of permanent deformation is prevented by causingeach tube to pass through a series of openings spaced along its lengthduring the drawing operation so as to restrict it laterally. Apparatusfor carrying forth the invention is shown in FIGS. 1, 2 and 4 andcomprises a first plurality of separable panel and platform devices 66at the forward end of the drawbench frame 10 as shown in FIGS. 1 and 2and a second plurality of elevatable platform devices 68 at the trailingor left end of the frame structure 10 as viewed in FIGS. 1 and 2. Theframe structure 10 may, therefore, be divided into Zone 1 along whichplatform devices 68 are spaced, and Zone 2 along which panel andplatform devices 66 are spaced. The main requirement of Zone 1 is thatit does not extend beyond the length of the shortest tube being drawn sothat at least the forward end of every drawn tube will extend into Zone2 before its trailing end snaps free of the die.

One of the separable panel devices is shown in FIG. 4 and comprises apair of upper and lower parts 70 and 72, respectively. Both parts 70 and72 are pivotally connected to a horizontal pin or axle 73 supported onthe upright portions 16 of the frame sections 12 in a scissors-typearrangement. The lower part 72 comprises an arm having an upper platform74 adapted to be rotated into position whereby the platform 74 isdirectly beneath the tubes 50 being drawn. The upper part 70, on theother hand, also comprises an arm which is movable from a position whereit is at an angle to horizontal to a position where it is in asubstantially horizontal plane with its major portion above the tubesbeing drawn.

Depending downwardly from the upper part 70 is a plate 76 having formedtherein a plurality of U-shaped openings 78 adapted to fit over thetubes being drawn with the lower edge 80 of the plate 76 being inabutment with the upper surface of platform 74. In order to raise andlower the upper part 70 about pin 73, a pneumatic cylinder 82 isprovided having its piston rod 84 connected through a clevis arrangement86 to an upstanding bracket 88 on the part 70. The other end of thepneumatic cylinder 82 is pivotally connected at 90 to an I-beam 92 whichextends along the entire drawbench frame 10 as shown in FIG. 1.

In a somewhat similar manner, the lower part 72 is actuated by means ofa pneumatic cylinder 94 having its one end pivotally connected at 96 toa second continuous I-beam 98 and its piston rod 100 connected through aclevis arrangement 102 to a downwardly-depending bracket 104 on the part72. Both of the parts 70 and 72 are constructed from welded plates andgussets, the details of which are unimportant as regards the presentinvention.

When the right ends of the cylinders 82 and 94 are pressurized, theparts 70 and 72 will be caused to pivot about pin 73 into abuttingrelationship with the lower edge 80 of plate 76 in abutment with theupper surface of platform 74. Pressurization of the cylinders 82 and 94in the opposite sense will cause the parts 70 and 72 to separate andassume positions at angles to the horizontal. With the part 72 in itslowermost position shown in FIG. 4, the platform 74 forms a common planewith surfaces 106 on the lower portions 14 of the frame sections 12 tothereby provide an inclined run-out table for the newly-drawn tubes.

The plurality of platform devices 68 at the forward end of the maindrawbench frame 10 in Zone 1 are sim;

ilar to the arrangement shown in FIG. 4, except that only the lower part72 is provided to support the tubes being drawn. It will be appreciatedthat in order for the draw carriage 30 to pass along the tracks 26 and28, the parts 70 and 72 must be the positions shown in FIG. 4.Consequently, the cylinders 82 and 94 can be pressurized to close theparts 70 and 72 only during a drawing operation and after the drawcarriage 30 has passed the position of a particular platform device 68in Zone 1 or panel device 66 in Zone 2 along the drawbench frame 10. Inthe drawing operation, and assuming that the draw carriage 30 isadjacent the die block 48 at the beginning of a drawing operation, themotor 44 will be energized to pull the draw carriage away from the dieblock 48, thereby pulling the tubes 50 through the dies. As the drawcarriage passes each platform device 68 in Zone 1, its associatedpneumatic cylinder 94 will be pressurized to elevate the part 72 shownin FIG. 4 and thereby move the platform 74 up into abutting relationshipbeneath the tubes being drawn. Likewise, as the draw carriage 30 passeseach of the panel devices 66 in Zone 2 as it moves away from the dieblock 48, the cylinders 82 and 94 will be pressurized to close the upperand lower parts 70 .and 72 shown in FIG. 4 whereby the tubes will beenveloped within an opening defined by the surface of platform 74 andthe periphery of an associated one of the U-shaped slots 78. Thesepositions are shown in dotted outline in FIG. 4. At the completion ofthe drawing operation when the tubes jump forwardly due to the releaseof kinetic energy, the U-shaped slots 78 of each panel device and theassociated platform 74 will prevent any substantial lateral deflectionof the tubes 50, thereby also preventing the formation of shock waves inthe tubes exceeding their elastic limits.

After all of the tubes have been drawn, the draw carriage is stopped,and the cylinders 82 and 94 pressurized to separate the upper and lowerparts 70 and 72 of each panel device 66 in Zone 2. Similarly, thecylinders 94 associated with the platform devices 68 in Zone 1 arepressurized to lower their associated platforms 74. In this process, itwill be appreciated that the previouslydrawn tubes will roll from theplatforms 74 onto the surfaces 106 and thence into a receiving bin, notshown, to the left of the frame sections 12 shown in FIG. 4. In thismanner, the arrangement facilitates a side-by-side and parallelrelationship of the newly-drawn tubes such that when the platforms 74move downwardly, the tubes will simply roll into a neat bundle in theaforesaid receiving bin preparatory to a succeeding drawing operation.

Circuitry for controlling the panel devices 66 and platform devices 68is also shown in FIG. 4 and includes a reversing valve 108 having oneport 110 connected to a source of air under pressure, not shown, andanother port 112 extending to the atmosphere. One delivery port of thevalve 108 is connected through conduit 114 to the forward ends of thepneumatic cylinders 82 and 94; while the other delivery port isconnected through conduit 116 to the rear ends of the cylinders 82 and94. With the valve 108 in the position shown in FIG. 4, the conduit 114will be pressurized to thereby cause the upper and lower parts 70 and 72to separate with the conduit 116 being connected to the atmospherethrough port 112. Reversal of the valve 108 will effect the oppositeresult with the conduit 116 being pressurized to cause the upper andlower parts 70 and 72 to converge until the edge 80 of the upper part 70is in abutment with the platform 74 of the lower part 72. Of course, inthe case of the plat form devices 68 in Zone 1, the valve 108 isconnected to cylinder 94 only.

The valve 108 is controlled by two solenoids 118 and 120. Provided alongthe main drawbench frame beyond each of the panel devices 66 is aone-way limit switch 122 which will be actuated only upon movement ofthe draw carriage away from the die block 48. The

. locations of switches 122 for Zone 2 are shown in FIG. 1.

Let us assume, for example, that the draw carriage has just passed theframe section 12 shown in FIG. 4 and has actuated the limit switch 122.Actuation of limit switch 122 closes contacts 124 to thereby energizethe relay 126. Relay 126 is held closed after actuation of the limitswitch 122 through a circuit including contacts 128 on relay 126 andnormally closed contacts 130 on a pushbutton switch 132. Thus, as thedraw carriage 30 passes each panel device 66, its associated limitswitch 122 will be closed to energize relay 126. Energization of relay126, in turn, closes contacts 134 to energize solenoid 118 and positionvalve 108 such that conduit 116 is pressurized to force the upper andlower parts 70 and 72 together. The operation is the same for theplatform devices 68 with the exception that only the lower part 72 andcylinder 94 are employed.

At the completion of the drawing operation when all tubes have passedthrough the dies, they will remain within the U-shaped slots 78.Thereafter, the pushbutton 132 is depressed. This pushbutton may, forexample, be that utilized to reverse the motor 44 and return the drawcarriage 30 to the die block 48. As the pushbutton 132 is depressed, itopens contacts 130, thereby breaking the holding circuit for relay 126and deenergizing solenoid 118. At the same time, depression ofpushbutton switch 132 closes contacts 136 to energize relay 138. Whenrelay 138 is energized, it is held energized through a holding circuitincluding normally open contacts 140 on the relay 138 and contacts 142on limit switch 122, which remain closed until the subsequent drawingoperation for the reason that the limit switch 122 is not actuated uponthe return stroke of the draw carriage. Energization of relay 138 alsocloses contacts 144, thereby energizing solenoid 120 to reverse thevalve 108 whereby conduit 114 is now pressurized to cause the upper andlower parts 70 and 72 to separate. Although the circuitry shown in FIG.4 is for one panel device only, it will be appreciated that the leads146 on pushbutton switch 132 are connected to the relays for all of thepanel devices 66 and platform devices 68 spaced along the main trackstructure 10 such that they will open simultaneously to permit the tubeson platforms 74 to roll into the aforesaid receiving bin and permit thedraw carriage to pass backwardly toward the die block 48. During thenext successive drawing operation, each limit switch 122 is actuated insuccession after the draw carriage passes its associated platform deviceor panel device to thereby again provide a plurality of openings throughwhich the tubes must pass and which prevent any substantial lateraldisplacement of the tubes.

Although the invention has been shown in connection with a certainspecific embodiment, it will be readily apparent to those skilled in theart that various changes in form and arrangement of parts may be made tosuit requirements without departing from the spirit and scope of theinvention. In this respect, it will be apparent that cables can besubstituted for the chains 38 and 40 within the skill of the art.

I claim as my invention:

1. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length, comprising rigid means for completelycircumferentially enveloping at least a portion of the workpiece betweensaid jaws and the die when the draw carriage moves away from the die tothereby prevent the development of said shock waves, the envelopingmeans being out of substantial frictional engagement with the workpiecewhile it is under tension during a drawing operation.

2. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length, comprising a plurality of substantiallyrigid devices spaced along the track structure for enveloping completelycircumferentially the workpiece between said jaws and the die when thedraw carriage moves away from the die to thereby prevent the developmentof said shock waves, the rigid devices being out of substantialfrictional engagement with the workpiece while it is under tensionduring a drawing operation.

3. The improvement of claim 2 wherein said plurality of substantiallyrigid devices are movable from points removed from the axis of the dieto points adjacent the axis of the die, and including means for movingsaid devices toward the axis of the die when the draw carriage movesaway from the die and for moving the devices away from the axis of thedie when the draw carriage moves toward the die.

4. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the relase of kinetic energy and the development ofshock waves along its length, comprising a first member positioned alongthe track structure and movable from a position removed from the centralaxis of the die to a position adjacent a workpiece being drawn, a secondmember positioned along the track structure on the side of the die axisopposite said first member and movable from a position removed from thecentral axis of the die to a position adjacent a workpiece being drawnand in substantial abutment with said first member, a generally U-shapedopening in the abutting surface of at least one of said members toprovide an opening which envelops but does not substantiallyfrictionally engage the workpiece when the members are in abutment andthe workpiece is under tension during a drawing operation, means formoving said members into abutment when the draw carriage moves away fromthe die and after it passes the position of the members along the trackstructure, and means for separating said members when the draw carriagemoves toward the die and before it passes the position of the membersalong the track structure.

5. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length, comprising a first plurality of memberspositioned along the track structure, each of said first members beingmovable from a position removed from the central axis of the die to aposition adjacent a workpiece being drawn, a second plurality of memberspositioned along the track structure on the side of the axis of the dieopposite said first members, each of said second members being movablefrom a position removed from the central axis of the die to a positionadjacent a workpiece being drawn and in substantial abutment with anassociated one of said first members, a generally U-shaped opening inthe abutting surface of at least one member of each associated pair ofabutting members to provide an opening which envelops but does notsubstantially frictionally engage the workpiece when the members are inabutment and the workpiece is under tension during a drawing operation,means for moving each pair of associated members into abutment when thedraw carriage moves away from the die and after it passes the positionof each pair of associated members along the track structure, and meansfor moving said members away from the central axis of the die when thedraw carriage moves toward the die and before it passes the position ofthe associated pair of members along the track structure.

6. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length comprising a first member positioned alongthe track structure and pivotally movable about a generally horizontalaxis from a position where it is at an angle to horizontal beneath theworkpiece to a position where it is in a generally horizontal planedirectly beneath the workpiece, a second member spaced along the trackstructure at the position of said first member and pivotal about agenerally horizontal axis, said second member being pivotally movablefrom a position where it is at an angle to horizontal above theworkpiece to a position where it is in a generally horizontal plane withits major portion above the workpiece and having a lower surface inabutment with said first member, and a generally U-shaped slot in saidsecond member adapted to fit over the workpiece when the second memberis in its generally horizontal position whereby the slot in the secondmember, in combination with the first member, will envelop but notsubstantially frictionally engage the workpiece when the workpiece isunder tension during a drawing operation, means for forcibly rotatingthe first and second members into their horizontal positions when thedraw carriage moves away from the die and after it passes the first andsecond members, and means for forcibly rotating the first and secondmembers into their positions at angles to the horizontal when the drawcarriage moves toward the die and before it passes the first and secondmembers.

7. The improvement of claim 6 wherein said first and second members arepivotal about a common horizontal axis, and wherein the means forforcibly rotating the members about their common horizontal axisincludes fluid cylinder means operatively connected to the members andlimit switch means adjacent the track structure adapted to be actuatedby passage of said draw carriage.

8. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length comprising a first plurality of memberspositioned along the track structure, each of said first members beingpivotally movable about a generally horizontal axis from a positionwhere it it at an angle to horizontal beneath the workpiece to aposition where it is in a generally horizontal plane directly beneaththe workpiece, a second plurality of members spaced along the trackstructure, each of said second members being in alignment with anassociated one of said first members and pivotally movable about agenerally horizontal axis from a position where it is at an angle tohorizontal above the workpiece to a position where it is in a generallyhorizontal plane with its major portion above the workpiece and having alower surface in abutment with an associated one of said first members,and a generally U-shaped slot in each of said second members adapted tofit over the workpiece when each second member is in its generallyhorizontal position whereby the slot in the second member, incombination with its associated first member, will envelop but notsubstantially frictionally engage the workpiece when the workpiece isunder tension during a drawing operation, means for forcibly rotatingeach of said associated first and second members into their horizontalpositions when the draw carriage moves away from the die and after itpasses each of said first and second associated members, and means forforcibly rotating each said associated first and second members intotheir positions at angles to the horizontal when the draw carriage movestoward the die.

9. The improvement of claim 8 and including an inclined run-out tablebeneath the track structure which lies in a common plane with the uppersurfaces of said second members when they are in their positions at anangle to horizontal.

10. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit moves away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length, comprising a plurality of scissors-likemechanisms having upper and lower arms pivotal about a horizontal axisat one side of the track structure and adapted to close and restrainlateral movement of a workpiece being drawn without substantiallyfrictionally engaging the same when the draw carriage moves away fromthe die during a drawing operation, said scissors-like devices eachbeing adapted to open to permit the draw carriage to pass therethroughupon movement of the draw carriage toward the die.

11. In a drawbench of the type having a drawing die, a track structureextending parallel to the axis of said die on one side thereof, and adraw carriage movable along said track structure and including jawswhich grip the forward end of a workpiece projecting through the die asit is moved away from the die; the improvement of means for preventingdamage to the workpiece as it is propelled forwardly at the completionof a draw due to the release of kinetic energy and the development ofshock waves along its length, comprising a first plurality of platformdevices spaced along the track structure at the end of the trackstructure nearest the die for supporting a drawn workpiece againstgravity and a second plurality of devices spaced along the trackstructure beyond the first plurality of platform devices for envelopingthe workpiece without substantially frictionally engaging the same as itis being drawn to thereby prevent the development of shock waves in theforward end of a workpiece enveloped by said second plurality ofdevices.

References Cited by the Examiner UNITED STATES PATENTS 3,107,006 10/63Myotte 205--3 3,175,385 3/65 Mitchell 72-281 CHARLES W. LANHAM, PrimaryExaminer,

1. IN A DRAWBENCH OF THE TYPE HAVING A DRAWING DIE, A TRACK STRUCTURE EXTENDING PARALLEL TO THE AXIS OF SAID DIE ON ONE SIDE THEREOF, AND A DRAW CARRIAGE MOVABLE ALONG SAID TRACK STRUCTURE AND INCLUDING JAWS WHICH GRIP THE FORWARD END OF A WORKPIECE PROJECTING THROUGH THE DIE AS IT MOVES AWAY FROM THE DIE; THE IMPROVEMENT OF MEANS FOR PREVENTING DAMAGE TO THE WORKPIECE AS IT IS PROPELLED FORWARDLY AT THE COMPLETION OF A DRAW DUE TO THE RELEASE OF KINETIC ENERGY AND THE DEVELOPMENT OF SHOCK WAVES ALONG ITS LENGTH, COMPRISING RIGID MEANS FOR COMPLETELY CIRCUMFERENTIALLY ENVELOPING AT LEAST A PORTION OF THE WORKPIECE BETWEEN SAID JAWS AND THE DIE WHEN THE DRAW CARRIAGE MOVES AWAY FROM THE DIE TO THEREBY PREVENT THE DEVELOPMENT OF SAID SHOCK WAVES, THE ENVELOPING MEANS BEING OUT OF SUBSTANTIAL FRICTIONAL ENGAGEMENT WITH THE WORKPIECE WHILE IT IS UNDER TENSION DURING A DRAWING OPERATION. 